The disposal of industrial chemical waste has been a long standing problem which is particularly acute today with popular demand and Government regulations for reducing pollution of the environment. However, it is a fact of life that chemical waste or residue is produced by almost every industrial process known to man.
In particular, in the Baton Rouge area of Louisiana there exist huge stock piles of waste products. One stock pile contains the residue or waste product from a process of digesting phosphate rock in sulfuric acid in an industrial process which leaves as a waste product calcium sulfate in an acid medium. Another stock pile contains the residue from an industrial process in which bauxite is digested in concentrated caustic soda, the residue being in the form of ponds of waste material containing clay, iron ore (Fe.sub.2 O.sub.3) and alumina (Al.sub.2 O.sub.3) in an alkaline medium.
These huge stock piles have existed for years because there was thought to be no use for them and because disposal of them by conventional methods would result in contamination of the environment. While attempts have been made to use waste gypsum from the reaction of phosphate rock with sulfuric acid to produce Portland cement, as disclosed in U.S. Pat. No. 3,717,489, it has not been used as in the present invention.